Abstract: Objective To analyze the epidemiological characteristics and investigation and disposal process of a tuberculosis epidemic in a middle school in Shenzhen during the COVID-19 epidemic, and provide reference experience for further standardizing the disposal of tuberculosis epidemics in schools. Method Field epidemiological methods were used to investigate and deal with the epidemic, and the epidemiological relevance of the epidemic was judged according to the time axis of the onset of cases, population distribution and gene sequencing results. All data were collected and sorted to analyze the causes of tuberculosis cluster in the school. Result From September 2020 to June 2021, a total of 8 cases of pulmonary tuberculosis were found, including 6 cases of laboratory diagnosis and 2 cases of clinical diagnosis. 7 cases were G senior students, with a student attack rate of 2.81%, and 1 case was a H senior student, with a student attack rate of 0.40%. There was a statistically significant difference in the attack rate between the two different grades (χ²=4.671, P<0.05). There were 2 females and 6 males. 2 cases (25.0%) were found in medical treatment due to symptoms, and 6 cases (75.0%) were found in close contact screening. In this outbreak, the latent infection rate of Mycobacterium tuberculosis among faculty and staff was 5.00% (4/80); the latent infection rate of Mycobacterium tuberculosis among students was 3.14% (36/1147), of which 12.5% (32/256) of the class with pulmonary tuberculosis cases were found, the class with no cases found was 0.48% (4/841), and the difference was statistically significant (χ²=89.403, P<0.001). Whole genome sequence analysis showed that case 1, case 3, case 4, case 5, and case 6 belonged to the same transmission chain;the strain of case 2 was a unique strain, and there was no transmission relationship with other positive patients. Conclusion Schools should implement tuberculosis health examination for students, and close contacts, especially those with latent Mycobacterium tuberculosis infection, are the focus groups of tuberculosis cluster epidemic in schools. During the period of COVID-19 epidemic prevention and control, all screening will be completed in schools, and joint prevention and control by all departments can effectively contain the tuberculosis epidemic in schools.

Key words: School, Tuberculosis, Epidemic prevention and control, Molecular epidemiology